A Letter of Mr. William Shervington to Benjamin Franklin, Esq; Of Philadelphia, concerning the Transit of Mercury Over the Sun, on the 6 of May 1753, as Observed in the Island of Antigua: Communicated by Mr. Peter Collinson, F. R. S.

XLVIII. A Letter of Mr. William Shervington to Benjamin Franklin, Esq; of Philadelphia, concerning the Transit of Mercury over the Sun, on the 6 of May 1753, as observed in the Island of Antigua: Communicated by Mr. Peter Collinson, F. R. S. SIR, Antigua, June 20, 1753. Read Nov. 15, 1753. Mr. Benjamin Mecom having received half a dozen circulatory letters from you relating to Mercury's transit over the sun the 6 of last May, he put them into my hands. One would have sufficed for our island, as we are not overburthen'd with men, who have a taste that way. Hereunder I send you the result of my observation * thereof. Sunday, May 6, at $6^h\ 7'\ 51''$, I observed the western limb of Mercury to touch the western limb of the sun; and, at $6^h\ 10'\ 37''$, he touch'd the same with his eastern limb, and totally disappear'd. Lat. of the place $17^\circ\ 0' N$. Lon. by estimation $61^\circ\ 45'$ W. from London. This was taken by a Graham's watch, and corrected by two altitudes taken by a most exquisite quadrant; viz. * Dr. Charles Rose, who was in Antigua at this time, says, that these observations were taken by Capt. Richard Tyrrel, of the said island, At 6h 58' 7", I observed the distance of the sun's upper limb from the zenith = 72° 21' 30". And, at 9h 31' 5", I observed the same = 36° 17' 0". By the common process (which you may have, if necessary) I found the watch was 0° 4' 4" 28" too fast *; therefore, \[ \begin{array}{cccc} \text{From} & = & = & 6 \ 10 \ 37 \\ \text{Take} & = & = & 0 \ 4 \ 4 \ 28 \\ \end{array} \] True apparent time of Mercs. exit here, 6 6 32 32 Pray impart your observation to Your Well-wisher, William Shervington. * Mr. Shervington has taken the mean of these two altitudes from the error of his watch; and there can be no doubt that his observation is a good one, which, compared with that made in Surry-street by Mr. Short, p. 199, l. i. &c. fixes the longitude of the place of his observation in Antigua 4h 5' 30", or 61° 22' 30", west of St. Paul's, London.